(bâr'ē-əm) Symbol BaA soft, silvery-white metallic element of the alkaline-earth group. It occurs only in combination with other elements, especially in barite. Barium compounds are used in x-raying the digestive system and in making fireworks and white pigments. Atomic number 56; atomic weight 137.33; melting point 725°C; boiling point 1,140°C; specific gravity 3.50; valence 2. See Periodic Table.

in ancient Egyptian religion, with the ka and the akh, a principal aspect of the soul; the ba appears in bird form, thus expressing the mobility of the soul after death. Originally written with the sign of the jabiru bird and thought to be an attribute of only the god-king, the ba was later represented by a man-headed hawk, often depicted hovering over the mummies of kings and commoners alike.